Duct access door

ABSTRACT

Apparatus for manufacturing door frames for insertion into a door opening, for example in air handling ducts and the like and comprising a door frame forming member having at least one bendable corner, and corner fastening means at a fourth corner whereby the frame member can be formed into a rectangular frame. The apparatus may include door latching means fastened to the frame member, and means for sealing the frame to a duct opening. In conjunction with the door frame apparatus the invention further comprises a door border apparatus, for use with door forming members such as rectangular metal door panels and the like, for making a door border channel member having at least one bendable corner, and a corner fastening means at a fourth corner whereby the channel can be formed into a rectangular border around such rectangular panels or the like, and including door securing means fastened to the channel for co-operation with the door latching means on the door frame.

United States Patent [191 Dayus Dec. 17, 1974 DUCT ACCESS DOOR [76] Inventor: Lloyd Giddis Dayus, 3400 Riverspray Dr., Mississauga, Ontario, Canada [22] Filed: May 21, 1973 [21] Appl. No.: 362,043

[52] U.S. Cl 49/504, 49/465, 52/658 [51] Int. Cl E06b l/04 [58] Field of Search 49/465, 466, 464, 463,

[56] References Cited UNITED STATES PATENTS 1,615,823 2/1927 Barclay 52/658 X 2,219,593 10/1940 Lang 49/504 X 2,384,929 9/1945 Kaufmann 1. 49/463 X 2,793,721 5/1957 Sterud 49/465 3,194,363 7/1965 Steffan et a1. 49/504 3,286,405 ll/1966 Schembri 49/463 3,348,337 10/1967 Grasso 49/503 X 3,376,669 4/1968 .lohnston.... 49/463 X 3,469,350 9/1969 Lange 1 1 49/504 3,537,212 11/1970 Gilles 49/465 X Primary ExaminerPaul R. Gilliam Assistant ExaminerPhilip C. Kannan ABSTRACT Apparatus for manufacturing door frames for insertion into a door opening, for example in air handling ducts and the like and comprising a door frame forming member having at least one bendable corner, and corner fastening means at a fourth corner whereby the frame member can be formed into a rectangular frame. The apparatus may include door latching means fastened to the frame member, and means for sealing the frame to a duct opening. ln conjunction with the door frame apparatus the invention further comprises a door border apparatus, for use with door forming members such as rectangular metal door panels and the like, for making a door border channel member having at least one bendable corner, and a corner fastening means at a fourth corner whereby the channel can be formed into a rectangular border around such rectangular panels or the like, and including door securing means fastened to the channel for co-operation with the door latching means on the door frame.

9 Claims, 8 Drawing Figures PATENTED UECI 71974 SHEET 3 OF DUCT ACCESS DOOR The present invention relates to inspection doors and frames for use in air conditioning ducts and the like, and in particular, to a kit for building such a door, and for building a door frame to accommodate the door, for installation in a duct.

BACKGROUND OF THE INVENTION Air conditioning ducts are installed with a variety of internal controls such as dampers, and other equipment such as heating and cooling coils, air filters, etc., and frequently are equipped with so called fire dampers which are designed to close off the ducts in the event of a tire. This equipment must be inspected and serviced from time to time, and of course, in the case of fire dampers, if the damper should be released by overheating, or by a fire then it must be reset once the condition has passed, so that the duct can be used once more.

In order to have access to the interior of the duct for these reasons it is necessary to provide some form of inspection door or trap door installed in the duct along side the damper or other control. Such doors may be thermally insulated, and are often sealed sufficiently well to withstand a certain predetermined elevated pressure. In the past, such doors have been made more or less or a custom basis by the installer of the duct work. As a result, it was a relatively time consuming procedure, and was unduly expensive.

Standardised doors and door frames have been manufactured which can be applied to ducts and simply fastened in position by the duct installer. However, these are not entirely satisfactory. In the first place, the installer will require doors of different sizes. In addition, the fastening of the frame to the duct work the fastening and the sealing of the door frame to the duct must be carried out with great care in order to achieve satisfactory results. Such door frames as are available are cumbersome and clumsy and require much timeconsuming labour to fasten them in position.

The manufacturing of standardized door and door frames, is also open to a more serious drawback, in that the cost of stocking and shipping the variety of sizes of doors and frames which may be required for any particular job will be so great as to render the doors and door frames unduly expensive except where local market conditions are favourable.

BRIEF SUMMARY OF THE INVENTION The invention therefore seeks to provide apparatus for manufacturing door frames for insertion into door openings, for example, in air handling ducts comprising a door frame forming member adapted to form a rectangular door frame having four comers; bendable means forming part of at least one of said four corners whereby said means may be bentsinto an acute angle for insertion of said frame forming member into a door opening, and, comer fastening means at a fourth corner whereby the frame member can be formed into a rectangular frame. The invention may also provide door latching means fastened to the frame member, and means for sealing the frame to a door opening. In conjunction with the door frame apparatus the invention further comprises a door border apparatus, for use with door forming members such as rectangular metal door panels and the like, for making a door to fit the door frame, the door border apparatus including a door border channel member having three bendable corners, and a corner fastening means at the fourth comer whereby the channel can be formed into a rectangular border around such rectangular panels or the like, and including door securing means fastenedto the channel for co-operation with the door latching means on the door frame.

The invention also seeks to provide a door frame, and door, when made and assembled as aforesaid.

More particularly, it is an objective of the invention to provide a door frame angle member formed out of a continuous roll formed angle strip, the strip defining a frame sidewall, a frame facing wall, and a channel formed along side the facing wall for inter-engagement with the edges of the door opening in the air handling duct for example, to form a good air tight seal.

More particularly, it is an objective of the invention to provide apparatus for manufacturing door frames having the foregoing advantages in which the angle member is formed with three spaced apart notched portions, whereby the same may be bent at three corners to form a rectangular frame, and including slotted means formed at said corners whereby the corners may be bent into acute angles to facilitate insertion of the frame into a door opening, as in an air handling duct.

The foregoing and other advantages will become apparent from the following description of a preferred embodiment of the invention which is given here by way of example only with reference to the following drawings in which like reference devises refer to like parts thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective illustration of an air handling duct, partially cut away, and showing a door and door frame, in accordance with the invention, fastened in position therein;

FIG. 2 is a perspective illustration of a portion of the door and door frame, partially cut away to show its construction;

FIG. 3 is a perspective illustration of an angle member for forming the door frame according to the invention, shown prior to bending into its rectangular shape;

FIG. 4 is a perspective illustration of the border channel for forming the door according to the invention, shown prior to bending into its rectangular shape, and,

FIGS. 5, 6, and 7 are schematic diagrams showing various stages of the insertion of the door frame into a rectangular opening in a duct, and,

FIG. 8 shows an alternate embodiment of the invention.

BRIEF DESCRIPTION OF A SPECIFIC EMBODIMENT Referring to FIG. I, a wall of an air duct 10 is shown which duct may be of rectangular shape in section. The duct 10 may incorporate some form of control means or damper means such as for example a fire damper, (not shown) and access may be required to the interior of the duct to service such control means or damper from time to time.

For this purpose, the door unit shown generally as 12 is provided in the sidewall of the duct by means of which access may be obtained to the interior of the duct as desired.

The door unit 12 will consist of a door shown generally as 14 and a door frame 16 which is fastened to the duct 10. It will of course be understood that a rectangular opening is formed in the duct 10, and the frame 16 is attached to the duct around the rectangular opening therein so as to enable the door 14 to be positioned in the door frame 16 to close the same off.

Any suitable form of fastening means such as the latching members 18 and the door securing members 20 are provided by means of which the door 14 may be secured in the door frame 16. A safety chain 22 may be attached between the door frame 16 and the door securing member 20 so that when the door 14 is removed it will hang from the chain 22.

Referring now to FIG. 2, it will be seen that the door 14 according to the invention comprises inner and outer rectangular rnetalic door panels 24 and 26, and sandwiched therebetween, a layer of thermal insulation material such as spun fibre glass 28, or other suitable material. The inner and outer panels 24 and 26 are held in their sandwiching relation by means of the door forming chanel 30 which comprises the central web 32, and the inner and outer side wall 34. Notch means are formed at the comers 36 whereby the channel 30 can be bent in to a rectangular shape as shown. Any suitable means may be provided at the fourth corner for fastening the same and securing it in its rectangular shape. Such means may comprise the fastening lip 38 as shown in FIG. 4, which is adapted to overlap the free end of the channel 30, and fastened for example by means of a rivet or the like through the hole 40 (see FIG. 4).

As shown in FIGS. 1 and 4, door securing means 20 may be fastened to opposite sides of the door forming channel 30, the door securing members 20 having inturned flanges 42 whereby the same may be grasped for manual removal of the door 14. In addition, the members 20 will preferably include some form of fastening means such as the L-shaped tongue members 44 struck out of the members 20. A hole 46 may be provided in one or both of the intumed flanges 42 for attachment of the chain 22 thereto.

The door frame 16 will preferably comprise a continuous angle member having a sidewall 50, and a facing wall 52 arranged at right angles thereto. Preferably, the outer edge of the side wall 50 is turned inwardly at 54. Along side the facing wall 52 is formed a narrow U- shaped channel, by means of the web 56 and inner wall 58. Preferably, the inner wall 58 and the facing wall 52 define a channel therebetween which is sufficient to receive the wall of the duct 10 therein forsecuring the door frame 16 in position in a rectangular opening in the duct. In order to provide a good air tight seal, a strip or bead of a suitable sealant material 60 is provided between the facing wall 52 and inner wall 58 which is of a suitable consistancy to remain relatively soft, and to flow around the edges of the opening formed in the duct 10 and make a good air tight seal therewith.

Butyl rubber is a particularly suitable sealant material and has the added advantage of providing a good adhesive bond'to the walls 52 and 58 and also to the edges of the duct. This material therefore acts as a spacefilling adhesive and aids in securing the frame to the duct.

Other sealant materials can also be employed such as foam plastic material.

Alternatively, a seal may be achieved by applying a suitable sealant to the edge of the ductwork itself. Such a sealant may be some form of adhesive tape, with a foam plastic or rubber backing, sufficient to fill the space between the duct work and the walls 52 and 58.

In order that the door frame 16 can be shipped flat and readily set up in position at a work site, it is provided with three readily bendable corners. These corners are formed by cutting notches 62 in the facing wall 52 and the inner wall 58 and also by forming notches 64 in the inturned outer edge 54 of the side wall 50. In this way, the side wall 50 provides bendable means which can readily be bent into a right-angle or an acute angle without difficulty.

In order to permit the corners of the door frame 16 to be bent into an acute angle, for insertion in the opening in the duct, additional slots 66 are formed in the web 56 so that the adjacent portions of the facing walls 52 and inner walls 58 may interleave with one another when the corners are bent to acute angles.

The latching members 18 are rotatably fastened to the side wall 50 of the door frames 16, and will be seen to be of a more or less irregular four-sided shape, roughly in the shape of a diamond, and are provided with a curved slotted opening 72, and a finger portion 74 whereby the member may be swung to and fro. Preferably, the curved slotted opening 72 is arranged so that its radius of curvature shortens slightly from its open end to its closed end so as to provide a slight camming action as it is closed around the tongue 44 of its respective member 20.

In order to close and lock the fourth comer of the door frame 16, an upturned locking member 76 is provided preferably indented as at 78, and the other end of the door frame 16 is preferably provided with an opening as at 80 to receive the indentation 78.

A strip 82 may be struck out of a portion of the side wall 50 of the frame 16 for attachment of the other end of the chain.

In operation, the duct work installer will receive the door frame member 16 and the door border channel member 30 shipped flat as shown in FIGS. 3 and 4. After having cut a suitable size of access opening in the duct, he will then bend the door frame member 16 at its three corners into acute angles as shown in FIG. 5. Having bent the door frame member 16 into this position, it can then be inserted into the opening in the duct, and the edge of the duct can be pushed into the channel formed between the facing wall 52 and the inner wall 58. The installer then gradually bends the various portions of the frame 16 outwardly as shown in FIG. 6, until all four sides are seated firmly around the edges of the duct as shown in FIG. 7.

In order to fasten the frame 16 in position he then simply flexes the wall 50, adjacent to the tongue 76 and twists it slightly so that the tongue 76 can be introduced between the adjacent end portions of the wall 50, and the turned-over edge portion 54, and slipped into position. The struck-out portion 78 will then engage with the hole 80, and the frame will then be secured in position.

In order to make the door 14 itself, he will simply cut two pieces of sheet metal into rectangular portions 24 and 26 as shown and take a portion of insulation material 28 and cut it into a similar rectangular shape and form it into a sandwich as shown in FIG. 2. He will then take the door forming channel 30 and bend it around the sandwich comprising the sheet metal portions 26 and 24 and the thermal insulation panel 28, and fasten the two ends of the channel by means of passing a rivet or self-tapping screw through the tongue 38 and through the opening 40.

All that is then necessary is to fasten the chain in postion.

In this way, a simple apparatus is provided for forming door frames and doors to fit the door frames, which may be supplied to the duct installer in a compact form, and yet in a form in which it is readily assembled in position at the site with a minimum of tools or special forming being required.

It will be understood that where market conditions are suitable, the door frames can be set up in the plant and shipped out already bent as shown, for insertion into a duct opening. The doors can also be completed and assembled in the factory and shipped out ready for installation.

In the case of larger door sizes additional fastening means may be provided where required on the frame and on the door to hold the same secure against the air pressure in the duct.

In some cases, it may be possible to provide a satisfactory frame with only a single bendable corner. Such a modified frame is shown in FIG. 8. The two corners shown as 90 will be simple mitred corners fastened into a right angle as shown and the third corner 92 will be of the flexible type as described above. Such a modified frame can also be insertedinto a duct opening in essentially the manner shown in FIGS. 5, 6, and 7.

In either case, the invention provides a door frame having corners, at least one of which incorporates bendable means whereby it can be bent into an acute angle to permit insertion into a door opening. Clearly, such opening can be in ductwork, or can be required in any other location where such a door may be installed, such as in any sheet metal, plastic, glass or wall panel of suitable thickness.

The foregoing is a description of a preferred embodiment of the invention which is given here by way of example only. The invention is not to be taken as limited to any of the specific features as described but comprehends all such variations thereof as come within the scope of the appended claims.

What I claim is:

1. Apparatus for manufacturing door frames for insertion into a door opening in a wall, for example in air handling ducts and the like, and comprising;

a door frame forming member adapted to form a rectangular door frame having four corners and defining a frame sidewall which may be set up into a rectangular frame, a frame facing wall extending from said frame sidewall in a generally L-shaped manner whereby to lie within the frame when the same is set up, channel means formed alongside the facing wall and remote from the sidewall and oriented to receive a portion of the wall surrounding the opening therewith, and,

notch means formed in said frame facing wall and said channel means at spaced intervals to permit bending of said frame sidewall for setting up as aforesaid, and,

means at at least one end of said frame forming member whereby the ends thereof may be fastened together when the same is in its rectangular position as aforesaid.

2. Apparatus for manufacturing door frames as claimed in claim 1 including door latching means fastened to the frame member, engagable with a door, when the same is seated in said frame.

3. Apparatus as claimed in claim 1 including sealing means arranged around said channel means for sealing between the same and said wall.

4. Apparatus as claimed in claim 1 wherein said frame forming member comprises a continuous strip of material formed with a frame side wall, a frame facing wall, and a channel means as aforesaid, and including;

notch means cut from said frame facing wall at three spaced intervals therealong defining three corners;

and wherein the notch means in said channel means comprises discontinuities in said channel means in registration will said notch means in said facing wall;

sealing means arranged around said channel whereby to make a good airtight seal between said frame forming member and said wall defining the opening and,

door latching means fastened to said frame side wall,

and engageable with a door when the same is seated in said frame.

5. Apparatus as claimed in claim 4 including door forming means for forming a door to be seated in said frame against said frame facing wall, and door securing means on said door forming means for interengagement with said door latching means.

6. Apparatus as claimed in claim I wherein said channel is formed by an inner wall lying alongside said facing wall, and web means joining the same along the free edge of said facing wall thereby directing said channel outwardly with respect to the frame when the same is set up.

7. Apparatus as claimed in claim 1 including door sealing means on said facing wall.

8. Apparatus as claimed in claim 6 including notch means formed in said webs at spaced intervals, and wherein said inner wall is cut away at spaced intervals, to facilitate bending of said side wall.

9. Apparatus as claimed in claim 1 including edge means on the edge of said side wall remote from said facing wall, folded over said side wall and including notch means cut therefrom at spaced intervals to facilitate bending thereof. 

1. Apparatus for manufacturing door frames for insertion into a door opening in a wall, for example in air handling ducts and the like, and comprising; a door frame forming member adapted to form a rectangular door frame having four corners and defining a frame sidewall which may be set up into a rectangular frame, a frame facing wall extending from said frame sidewall in a generally L-shaped manner whereby to lie within the frame when the same is set up, channel means formed alongside the facing wall and remote from the sidewall and oriented to receive a portion of the wall surrounding the opening therewith, and, notch means formed in said frame facing wall and said channel means at spaced intervals to permit bending of said frame sidewall for setting up as aforesaid, and, means at at least one end of said frame forming member whereby the ends thereof may be fastened together when the same is in its rectangular position as aforesaid.
 2. Apparatus for manufacturing door frames as claimed in claim 1 including door latching means fastened to the frame member, engagable with a door, when the same is seated in said frame.
 3. Apparatus as claimed in claim 1 including sealing means arranged around said channel means for sealing between the same and said wall.
 4. Apparatus as claimed in claim 1 wherein said frame forming member comprises a continuous strip of material formed with a frame side wall, a frame facing wall, and a channel means as aforesaid, and including; notch means cut from said frame facing wall at three spaced intervals therealong defining three corners; and wherein the notch means in said channel means comprises discontinuities in said channel means in registration will said notch means in said facing wall; sealing means arranged around said channel whereby to make a good airtight seal between said frame forming member and said wall defining the opening and, door latching means fastened to said frame side wall, and engageable with a door when the same is seated in said frame.
 5. Apparatus as claimed in claim 4 including door forming means for forming a door to be seated in said frame against said frame facing wall, and door securing means on said door forming means for interengagement with said door latching means.
 6. Apparatus as claimed in claim 1 wherein said channel is formed by an inner wall lying alongside said facing wall, and web means joining the same along the free edge of said facing wall thereby directing said channel outwardly with respect to the frame when the same is set up.
 7. Apparatus as claimed in claim 1 including door sealing means on said facing wall.
 8. Apparatus as claimed in claim 6 including notch means formed in said webs at spaced intervals, and wherein said inner wall is cut away at spaced intervals, to facilitate bending of said side wall.
 9. Apparatus as Claimed in claim 1 including edge means on the edge of said side wall remote from said facing wall, folded over said side wall and including notch means cut therefrom at spaced intervals to facilitate bending thereof. 